1. Field of the Invention
The present invention relates to a horn switch assembly for vehicles, and more particularly to a horn switch assembly for vehicles wherein a horn switch is disposed between an airbag housing and an airbag cover so that only the airbag cover is supported by means of springs.
2. Description of the Related Art
Generally, a horn switch is a device that is on/off by a manipulation of a driver for connecting an electricity source to a horn sounding an alarm or disconnecting the electricity source from the horn. The horn switch is mounted in a steering wheel together with a driver airbag module.
FIG. 1 is an exploded perspective view showing a conventional horn switch assembly for vehicles, and FIG. 2 is a side view showing the conventional horn switch assembly for vehicles.
As shown in FIGS. 1 and 2, the conventional horn switch assembly for vehicles comprises: a horn plate 2 disposed under an airbag module 10 vertically slidably attached to a steering wheel, the horn plate 2 being attached to a hub of the steering wheel by means of bolts; a plurality of studs 4 each of which has one end attached to the horn plate 2 and the other end fitted in the airbag module 10; a plurality of coil springs 6 each of which is vertically wound on the circumference of the corresponding stud 4 for upwardly supporting the airbag module 10; a plurality of stationary terminals 7 mounted to the horn plate 2; and a plurality of movable terminals 8 mounted to the airbag module 10, the movable terminals 8 being connected to or disconnected from the stationary terminals 7, respectively, by means of a vertical sliding movement of the airbag module 10.
Each of the coil springs 6 has a prescribed elastic force so that the coil springs 6 are easily compressed when a driver pushes down the airbag module 10 while the coil springs 6 upwardly support the airbag module 10 so that the movable terminals are vertically spaced apart from the stationary terminals 7, respectively.
The operation of the conventional horn switch assembly for vehicles with the above-stated construction will now be described.
When the driver pushes down the airbag module 10 in the direction indicated by an arrow F in FIG. 2, the airbag module 10 is moved downward toward the horn plate 2 against the elastic force of the coil springs 6. As a result, the movable terminals 8 make contact with the stationary terminals 7, respectively, so that the horn is energized to sound an alarm.
After the driver stops pushing down the airbag module 10, the airbag module 10 is moved upward by virtue of the elastic force of the coil springs 6. As a result, the movable terminals are vertically spaced apart from the stationary terminals 7, respectively, so that the horn is no longer energized. Consequently, no alarm is sounded from the horn.
In the conventional horn switch assembly for vehicles, it is required that each of the coil springs 6 have high rigidity because the coil spring 6 must support the airbag module 10. However, space for the hub of the steering wheel is very limited, and thus design of the horn switch assembly is restricted due to its interference with the hub of the steering wheel and with the airbag module 10.
Furthermore, the force necessary to manipulate the horn switch is increased as the rigidity of the coil springs 6 is increased, which may bring about consumer dissatisfaction.
In the conventional horn switch assembly for vehicles, the horn plate 2 is attached to the steering wheel by means of the bolts after the studs 4, the coil springs 6, and the stationary terminals 7 are mounted to the horn plate 2. In case of the airbag module 10 comprising an airbag cover 12 and an airbag housing 14, the airbag cover 12 is attached to the airbag housing 14, the airbag cover 12 is attached to the airbag housing 14 by means of bolts so that the airbag cover 12 is moved simultaneously with the airbag housing 14. Consequently, the assembly operation of the conventional horn switch assembly for vehicles is very complicated.
Moreover, the airbag module 10 is mounted in the steering wheel together with the horn switch. Consequently, design of the airbag module 10 may be restricted due to the rigidity of the coil springs 6.